Development of a rehabilitation robot to provide therapy to patients with hand function deficits, due to stroke and traumatic brain injury, is proposed. The robot will provide repetitive opening and closing of the digits of the fingers of the hand in a manner that provides 1) sensory feedback similar to that a hand would experience when grasping an object, 2) modulation of applied forces commensurate with the patient's level of function, and 3) frees the therapist from the need to manually move the limb/joint through its cycle. The robotic mechanism will be designed to permit the patient to grasp and release an object in a manner that replicates the normal kinematics of grasping. The robot can provide passive range of motion but will use feedback (muscle EMG for the early stages of rehabilitation of a very weak hand, force feedback once active motion is detected) to adjust the assistance it provides to the patient's attempts to initiate or carry out a grasping maneuver. [unreadable] Phase I will initiate development of the proposed robot, including design, construction, and bench testing of a computer-controlled robotic system prototype. Upon completion of bench testing, the system will be evaluated by researchers and clinicians at the Mayo Clinic in Rochester. In Phase II, the utility of a more complete robot prototype, with assistance to the patient based on force and EMG feedback, will be assessed in a randomized, controlled clinical evaluation of the device at the Mayo Clinic. This evaluation would involve patients who have neurological hand impairments and would be designed to compare robotic assisted therapy against the best conventional care. [unreadable] [unreadable]